A Study Assessing the Association of Glycated Hemoglobin A1C (HbA1C) Associated Variants with HbA1C,Chronic Kidney Disease and Diabetic Retinopathy in Populations of Asian Ancestry

Glycated hemoglobin A_1C (HbA_1C) level is used as a diagnostic marker for diabetes mellitus and a predictor of diabetes associated complications. Genome-wide association studies have identified genetic variants associated with HbA_1C level. Most of these studies have been conducted in populations of European ancestry. Here we report the findings from a meta-analysis of genome-wide association studies of HbA_1C levels in 6,682 non-diabetic subjects of Chinese, Malay and South Asian ancestries. We also sought to examine the associations between HbA_1C associated SNPs and microvascular complications associated with diabetes mellitus, namely chronic kidney disease and retinopathy. A cluster of 6 SNPs on chromosome 17 showed an association with HbA_1C which achieved genome-wide significance in the Malays but not in Chinese and Asian Indians. No other variants achieved genome-wide significance in the individual studies or in the meta-analysis. When we investigated the reproducibility of the findings that emerged from the European studies, six loci out of fifteen were found to be associated with HbA_1C with effect sizes similar to those reported in the populations of European ancestry and P-value ≤ 0.05. No convincing associations with chronic kidney disease and retinopathy were identified in this study.     

Activation of Olfactory Receptors on Mouse Pulmonary Macrophages Promotes Monocyte Chemotactic Protein-1 Production

Background

Emerging evidence suggests that non-olfactory tissues and cells can express olfactory receptors (ORs), however, the exact function of ectopic OR expression remains unknown. We have previously shown in mouse models that a unique cooperation between interferon-γ (IFN-γ) and lipopolysaccharide (LPS) drives the activation of pulmonary macrophages and leads to the induction of pathogenic responses in the respiratory tract. Further, through gene array studies, we have shown that activation of macrophages by these molecules results in the selective expression of a number of ORs. In this study, we validated the expression of these ORs in mouse airway and pulmonary macrophages in response to IFN-γ and LPS (γ/LPS) stimulation, and further explored the effect of odorant stimulation on macrophage function.

Methodology/Principal Findings

OR expression in airway and pulmonary macrophages in response to IFN-γ, LPS or γ/LPS treatments was assessed by microarray and validated by q-PCR. OR expression (e.g. OR622) on macrophages was confirmed by visualization in immunofluoresence assays. Functional responses to odorants were assessed by quantifying inflammatory cytokine and chemokine expression using q-PCR and cell migration was assessed by a modified Boyden chamber migration assay. Our results demonstrate that eight ORs are expressed at basal levels in both airway and pulmonary macrophages, and that γ/LPS stimulation cooperatively increased this expression. Pulmonary macrophages exposed to the combined treatment of γ/LPS+octanal (an odorant) exhibited a 3-fold increase in MCP-1 protein production, compared to cells treated with γ/LPS alone. Supernatants from γ/LPS+octanal exposed macrophages also increased macrophage migration in vitro.

Conclusions/Significance

Eight different ORs are expressed at basal levels in pulmonary macrophages and expression is upregulated by the synergistic action of γ/LPS. Octanal stimulation further increased MCP-1 production and the motility of macrophages. Our results suggest that ORs may mediate macrophage function by regulating MCP-1 production and cell migration.     

HER2 Amplification and Clinicopathological Characteristics in a Large Asian Cohort of Rare Mucinous Ovarian Cancer

Mucinous epithelial ovarian cancer has a poor prognosis in the advanced stages and responds poorly to conventional chemotherapy. We aim to elucidate the clinicopathological factors and incidence of HER2 expression of this cancer in a large Asian retrospective cohort from Singapore. Of a total of 133 cases, the median age at diagnosis was 48.3 years (range, 15.8–89.0 years), comparatively younger than western cohorts. Most were Chinese (71%), followed by Malays (16%), others (9.0%), and Indians (5%). 24% were noted to have a significant family history of malignancy of which breast and gastrointestinal cancers the most prominent. Majority of the patients (80%) had stage I disease at diagnosis. Information on HER2 status was available in 113 cases (85%). Of these, 31 cases (27.4%) were HER2+, higher than 18.8% reported in western population. HER2 positivity appeared to be lower among Chinese and higher among Malays patients (p = 0.052). With the current standard of care, there was no discernible impact of HER2 status on overall survival. (HR = 1.79; 95% CI, 0.66–4.85; p = 0.249). On the other hand, positive family history of cancer, presence of lymphovascular invasion, and ovarian surface involvements were significantly associated with inferior overall survival on univariate and continued to be statistically significant after adjustment for stage. While these clinical factors identify high risk patients, it is promising that the finding of a high incidence of HER2 in our Asian population may allow development of a HER2 targeted therapy to improve the management of mucinous ovarian cancers.     

The Impact of Prolonged Storage of Red Blood Cells on Cancer Survival

Background

The duration of storage of transfused red blood cells (RBC) has been associated with poor clinical outcomes in some studies. We sought to establish whether prolonged storage of transfused RBC in cancer patients influences overall survival (OS) or cancer recurrence.

Methods and Findings

Patients diagnosed with cancer at The Ottawa Regional Cancer Centre between January 01, 2000 and December 31, 2005 were included (n = 27,591) where 1,929 (7.0%) received RBC transfusions within one year from diagnosis. Transfused RBC units were categorized as “new” if stored for less than 14 days, “intermediate” if stored between 14 and 28 days and “old” if stored for more than 28 days. Baseline characteristics between the comparative groups were compared by ANOVA test. Categorical variables and continuous variables were compared using Chi-squared and Wilcoxan rank-sum tests respectively. Overall survival was not associated with duration of storage of transfused RBC with a median survival of 1.2, 1.7, 1.1 years for only new, intermediate and old RBC units respectively (p = 0.36). Cancer recurrence was significantly higher in patients who received a RBC transfusion than those who did not (56.3% vs 33.0% respectively; p<0.0001) but was not affected by the duration of storage of transfused RBC (p = 0.06). In multivariate analysis, lung cancer, advanced stage, chemotherapy, radiation, cancer-related surgery and cancer recurrence were associated with inferior OS (p<0.05), while age, advanced stage, lung cancer, and more than 6 units of blood transfused were associated with cancer recurrence (p<0.05). The duration of storage of RBC before transfusion was not associated with OS or cancer recurrence in multivariate analysis.

Conclusion

In patients diagnosed with cancer, the duration of storage of transfused RBC had no impact on OS or cancer recurrence. This suggests that our current RBC storage policy of providing RBC of variable duration of storage for patients with malignancy is safe.     

Neural development in human embryonic stem cells-applications of lentiviral vectors

The derivation of neural lineages from human embryonic stem cells (hESCs) in vitro is based largely on exposure of hESCs to exogenous signals and substrates, designed to mimic conditions in the developing embryo. However, selection of specific lineages and the discovery of gene function in human neural development may be enhanced by the ability to intrinsically regulate gene expression. Recombinant lentiviral vectors provide an efficient method to stably introduce genes into hESC and their differentiating derivatives. Here we review the methods used to derive neural cells from hESCs, transduction of these cells with lentiviral vectors, and improvements that have been made to the vectors to enhance viral integration and transgene expression. Finally, we explore prospects for future uses of lentiviral vectors in hESC research, including their applications in library screening for drug development, zinc finger nucleases for gene editing and optogenetics to interrogate cellular pathways and function.     

Assessment of a bioaugmentation strategy with polyphosphate accumulating organisms in a nitrification/denitrification sequencing batch reactor

Different alternative configurations and strategies for the simultaneous biological removal of organic matter and nutrients (N and P) in wastewater have been proposed in the literature. This work demonstrates a new successful strategy to bring in enhanced biological phosphorus removal (EBPR) to a conventional nitrification/denitrification system by means of bioaugmentation with an enriched culture of phosphorus accumulating organisms (PAO). This strategy was tested in a sequencing batch reactor (SBR), where an 8 h configuration with 3 h anoxic, 4.5 h aerobic and 25 min of settling confirmed that nitrification, denitrification and PAO activity could be maintained for a minimum of 60 days of operation after the bioaugmentation step. The successful bioaugmentation strategy opens new possibilities for retrofitting full-scale WWTP originally designed for only nitrification/denitrification. These systems could remove P simultaneously to COD and N if they were bioaugmented with waste purge of an anaerobic/aerobic SBR operated in parallel treating part of the influent wastewater.     

Conservation of all three p53 family members and Mdm2 and Mdm4 in the cartilaginous fish

Analysis of the genome of the elephant shark (Callorhinchus milii), a member of the cartilaginous fishes (class Chondrichthyes), reveals that it encodes all three members of the p53 gene family, p53, p63 and p73, each with clear homology to the equivalent gene in bony vertebrates (class Osteichthyes). Thus, the gene duplication events that lead to the presence of three family members in the vertebrates dates to before the Silurian era. It also encodes Mdm2 and Mdm4 genes but does not encode the p19^Arf gene. Detailed comparison of the amino acid sequences of these proteins in the vertebrates reveals that they are evolving at highly distinctive rates, and this variation occurs not only between the three family members but extends to distinct domains in each protein.Key words: p53, p63, p73, Mdm2, Mdm4, elephant shark     

Transferability of type 2 diabetes implicated loci in multi-ethnic cohorts from Southeast Asia

Recent large genome-wide association studies (GWAS) have identified multiple loci which harbor genetic variants associated with type 2 diabetes mellitus (T2D), many of which encode proteins not previously suspected to be involved in the pathogenesis of T2D. Most GWAS for T2D have focused on populations of European descent, and GWAS conducted in other populations with different ancestry offer a unique opportunity to study the genetic architecture of T2D. We performed genome-wide association scans for T2D in 3,955 Chinese (2,010 cases, 1,945 controls), 2,034 Malays (794 cases, 1,240 controls), and 2,146 Asian Indians (977 cases, 1,169 controls). In addition to the search for novel variants implicated in T2D, these multi-ethnic cohorts serve to assess the transferability and relevance of the previous findings from European descent populations in the three major ethnic populations of Asia, comprising half of the world's population. Of the SNPs associated with T2D in previous GWAS, only variants at CDKAL1 and HHEX/IDE/KIF11 showed the strongest association with T2D in the meta-analysis including all three ethnic groups. However, consistent direction of effect was observed for many of the other SNPs in our study and in those carried out in European populations. Close examination of the associations at both the CDKAL1 and HHEX/IDE/KIF11 loci provided some evidence of locus and allelic heterogeneity in relation to the associations with T2D. We also detected variation in linkage disequilibrium between populations for most of these loci that have been previously identified. These factors, combined with limited statistical power, may contribute to the failure to detect associations across populations of diverse ethnicity. These findings highlight the value of surveying across diverse racial/ethnic groups towards the fine-mapping efforts for the casual variants and also of the search for variants, which may be population-specific.     

Genome-wide meta-analysis of five Asian cohorts identifies PDGFRA as a susceptibility locus for corneal astigmatism

Corneal astigmatism refers to refractive abnormalities and irregularities in the curvature of the cornea, and this interferes with light being accurately focused at a single point in the eye. This ametropic condition is highly prevalent, influences visual acuity, and is a highly heritable trait. There is currently a paucity of research in the genetic etiology of corneal astigmatism. Here we report the results from five genome-wide association studies of corneal astigmatism across three Asian populations, with an initial discovery set of 4,254 Chinese and Malay individuals consisting of 2,249 cases and 2,005 controls. Replication was obtained from three surveys comprising of 2,139 Indians, an additional 929 Chinese children, and an independent 397 Chinese family trios. Variants in PDGFRA on chromosome 4q12 (lead SNP: rs7677751, allelic odds ratio?=?1.26 (95% CI: 1.16-1.36), P(meta)?=?7.87×10(-9)) were identified to be significantly associated with corneal astigmatism, exhibiting consistent effect sizes across all five cohorts. This highlights the potential role of variants in PDGFRA in the genetic etiology of corneal astigmatism across diverse Asian populations.